1. Field
One embodiment of the invention relates to a video signal processing apparatus and method, which are preferably used for a television receiver, a video signal recording/reproducing apparatus, and a set top box.
2. Description of the Related Art
A variety of types of video signals have been used for a television receiver in recent years. For example, an interlace video signal, and a film signal that is electrically converted from an interlace video signal and a film image. Various aspect ratios are also available. Accordingly, a video signal processing apparatus is required to have an IP conversion function to convert an interlace signal to a progressive (non-interlace) video signal. A view angle conversion function is also required to change the aspect ratio of an image displayed on a screen to 4:3 or 16:9, or to change the display mode to zoom, wide or super-live, etc. An image quality adjustment function is also required. Further, as a display size is increased, a frame rate conversion function is required to convert scanning lines at double speed for example.
To satisfy the above requirements, movement of an image is detected by an image movement detection circuit, and an interpolation signal is generated by an interpolation circuit according to the detected image movement. There is an apparatus which reduces noise by using information about the image movement detected by an image movement detection circuit (e.g., Patent Document 1: U.S. patent application Ser. No. 2007/0058712A1 (International Publication No. W02004/112378)).
The film signal described above is also called a 2-3pull-down signal or a 2-2pull-down signal. As an interlace signal or a progressive signal exists in such a film signal, the above-mentioned IP conversion function, view angle conversion function, image quality adjustment function and frame rate conversion function are required. IP conversion of a film signal is different from IP conversion of a video signal of an ordinary television standard. The technique for IP conversion of a film signal is disclosed in Patent Document 2 (U.S. patent application Ser. No. 2005/0134735A1 (Japanese Patent Application No. 2005-208613)).
As described above, various types of input video signal have been used, and a video signal processing apparatus requires an IP conversion function, a view angle conversion function, an image quality adjustment function and a frame rate conversion function. In the prior art, a video signal processing apparatus is improved individually for each requirement disclosed in the above Patent Documents.
In the prior art, there is no video signal processing apparatus applicable to all types of input video signal. There is also no video signal processing apparatus operable stably for various types of input video signal. Namely, in the prior art, there is no technique for integrally combining an IP conversion function, a view angle conversion function, an image quality adjustment function, and a frame rate conversion function that does not involve problems.